Despite existing studies on teachers' emotional labour having been primarily correlational in nature, most researchers to date have assumed teachers' emotional labour to predict well-being outcomes (e.g. job satisfaction, burnout). Moreover, although it is commonly understood that teachers strategically manipulate their expressions of emotions (e.g. intentional displays of anger or disappointment) as effective classroom management strategies, the predictive relationship between their emotional labour and student engagement lacks empirical investigation. The present short-term longitudinal study addresses these research gaps by evaluating the directionality of relationships between teachers' emotional labour, psychological well-being, and perceived student engagement in 1,086 Canadian practicing teachers. Structural equation modelling analyses showed both teachers' well-being and perceived student engagement to directly predict their use of emotional labour strategies rather than vice versa. Further theoretical and pedagogical development implications are discussed.